Chemical pollution poses a major threat to environmental and human health, necessitating efficient remediation strategies. Photocatalysis offers a promising approach, yet its effectiveness is often limited by charge recombination and surface reactivity. Here, we investigate aliovalent doping of strontium titanate (SrTiO3) with aluminum to enhance photocatalytic degradation of organic pollutants, including the anionic dye methyl orange and the chlorinated pesticide 2,4-dichlorophenoxyacetic acid (2,4-D). SrTiO3 nanoparticles were synthesized via solid-state reaction and subjected to flux-mediated Al doping (0–20 mol %). High-resolution electron microscopy revealed a previously unreported Al-enriched surface layer at high doping levels (>5 mol %), which correlates with reduced photocatalytic activity. The highest degradation rate was observed for nominally undoped samples (0 mol % Al, sourced from the crucible), suggesting surface Al accumulation inhibits charge migration and pollutant adsorption. Scavenger experiments identified superoxide anions as key reactive species. Furthermore, C–Cl bond cleavage in 2,4-D confirms the material’s potential for remediating persistent organic pollutants. These findings provide mechanistic insight into dopant distribution and surface effects, guiding future design of photocatalysts for environmental applications.
Day et al. (Sat,) studied this question.